Michael Black wrote:
At least some of those are audio bandwidth transistors, the HRO-500 of
course needs transistors good in the shortwave and low VHF segment.

I expect they are there too. The ones I am interested are for yellow
boxes made around 1963 which use audio transistors. Most of them are
either oscillators to boost DC voltage, some are dc amplifiers.


I just know I've seen people writing about restoring their HRO-500s and
other things with germanium diodes, and getting replacements has been some
sort of an issue.


The Soviet D9b diodes make great detectors and are about a penny each,
including postage. They were half that because the lower case b in the
Cyrilic (Russian) alphabet looks like a number 5, and they were listed
as D95 diodes, which no one could find any specs on.

I think I had something to do with the price rise, when I commented on
the price on several groups, the listings were fixed and the price went up.

There even are 1n34a diodes still made with germanium in them. Most of the
so called germanium diodes are actualy silicon. They make finding the
real ones difficult as eBay vendors don't differentiate.

I have a few UK germanium diodes, that have real gold in them, and are
much better detectors. I found them on eBay for 1 UKP each. I am saving
them for a special project, when I think of it.


I probably have some germanium transistors around, unless I tossed them.
There was a period in the seventies when the local electronic store, which
also sold surplus (Etco Electronics, they later moved their base to the US
to do mailorder) was offering great deals on germanium transistors, but
their selling point wasn't that they were germanium. It was that they had
good frequency response. I did buy a lot of those back then.


If you can look up what they were, I would be interested in finding out.

Geoff.


--
Geoffrey S. Mendelson, N3OWJ/4X1GM/KBUH7245/KBUW5379